Error 5142



Message text

Mirroring for device ’%.*s’ is not currently enabled.


Error 5142 is raised when you execute a disk unmirror command in retain mode, but the device in question is not currently mirrored.

Disk mirroring is automatically deactivated when a read or write to a mirrored device fails. You may see error 5142, possibly accompanied by additional messages at the console or in the error log if:


Take the following steps:

  1. Look at the server error log. Check for additional errors preceding the 5142 error to determine the probable cause. For example, an “udunmirror” kernel error indicates a physical disk problem leading to I/O failure; for corrective action, refer to the write-up for “udunmirror errors” in this manual.

  2. If the device was recently mirrored or remirrored, check the procedure used to set up the mirror. Since a database device and its mirror constitute one logical device, you should not initialize the mirror device with disk init. Also check the syntax used for the disk mirror command, ensuring that the path to the mirror is properly specified. Finally, check disk configuration and make sure the disk is properly labeled.

Additional information

To retain use of asynchronous I/O, always mirror devices that are capable of asynchronous I/O to other devices capable of asynchronous I/O. On platforms that do not support asynchronous I/O for file system devices, you must mirror raw devices to raw devices and file system files to file system files.

Refer to “Initializing Mirrors” in the chapter “Mirroring Database Devices” in the System Administration Guide: Volume 2 for details.

Versions in which this error is raised

All versions